Method and apparatus for laser shock peening ballistic armor

Abstract

Ballistic failure resistance is imparted to metallic ballistic armor plate by identifying a compressive residual stress profile for mitigating a predetermined ballistic failure mode in a metallic ballistic armor plate component, and imparting the identified compressive residual stress profile to the component by laser peening the component in a treatment mode predetermined with reference to the identified compressive residual stress profile.

What is claimed is: 
     
       1. A method for imparting a predetermined surface contour to a metallic ballistic armor plate component, the method comprising:
 identifying a first compressive residual stress profile for providing the metallic ballistic armor plate component with the predetermined surface contour; and 
 laser peening a surface of the metallic ballistic armor plate component in a first treatment mode predetermined with reference to the first identified compressive residual stress profile, thereby inducing plastic deformation in the metallic ballistic armor plate component and thereby imparting a predetermined surface contour to the metallic ballistic armor plate component that is a different surface contour than the metallic ballistic armor plate had prior to the laser peening. 
 
     
     
       2. The method of  claim 1 , wherein the first identified compressive residual stress profile is identified by imparting controlled compressive residual stress profiles to the surface of the metallic ballistic armor plate components, measuring surface contours provided by the imparted compressive residual stress profiles, selecting a measured surface contour, and identifying the imparted compressive residual stress profile corresponding to the selected measured surface contour. 
     
     
       3. The method of  claim 1 , wherein the first identified compressive residual stress profile has a predetermined value of depth or shape on the surface. 
     
     
       4. The method of  claim 1 , wherein the first treatment mode has a predetermined value of laser beam energy, pulse width, rise time, spot diameter, spot area, spot overlap, or spot shape. 
     
     
       5. The method of  claim 1 , wherein the plastic deformation is directly induced in the metallic ballistic armor plate component at a weld on the surface. 
     
     
       6. The method of  claim 1 , wherein the predetermined surface contour imparted to the metallic ballistic armor plate component is non-planar. 
     
     
       7. The method of  claim 1 , wherein the predetermined surface contour imparted to the metallic ballistic armor plate component is planar. 
     
     
       8. The method of  claim 1 , further comprising:
 identifying a second compressive residual stress profile for mitigating a predetermined ballistic failure mode in the metallic ballistic armor plate component; and 
 laser peening the metallic ballistic armor plate component in a second treatment mode predetermined with reference to the identified second compressive residual stress profile, thereby imparting the second identified compressive residual stress profile to the metallic ballistic armor plate component. 
 
     
     
       9. The method of  claim 1 , wherein the predetermined ballistic failure mode comprises shear plugging, spalling, or scabbing. 
     
     
       10. The method of  claim 1 , wherein the second identified compressive residual stress profile is identified by inducing controlled compressive residual stress profiles to metallic ballistic armor plate components, measuring resistance to the predetermined ballistic failure mode imparted by the induced compressive residual stress profiles, selecting a measured resistance, and identifying the induced compressive residual stress profile corresponding to the selected measured resistance. 
     
     
       11. The method of  claim 1 , wherein the second identified compressive residual stress profile has a predetermined value of depth or shape. 
     
     
       12. The method of  claim 1 , wherein the second treatment mode has a predetermined value of laser beam energy, pulse width, rise time, spot diameter, spot area, spot overlap or spot shape. 
     
     
       13. The method of  claim 1 , wherein the second identified compressive residual stress profile is imparted to the ballistic armor plate component at a weld in the metallic ballistic armor plate component. 
     
     
       14. The method of  claim 1 , wherein the first treatment mode and the second treatment mode are the same.